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Landscape Management for Schuster Slope

The City of Tacoma and Metro Parks are in the process of developing a strategy for managing the steep, undeveloped slope above Schuster Parkway. At a public meeting this week interested members of the public will have the opportunity to learn about the challenges they're trying to address, and the solutions they've come up with.

The Schuster Slope project area runs from the northern edge of Tacoma's downtown, just below the Stadium District, along the Schuster Parkway corridor, all the way to the edge of the Garfield Gulch, just short of Old Town.

As a slice of undeveloped open space that's primarily been left in a natural undeveloped state, it provides important environmental benefits. It helps manage stormwater, provides wildlife habitat and protects water quality.

It's for these reasons that the City of Tacoma's Environmental Services Department is caretaker to select open spaces, such as the Schuster Slope, throughout Tacoma. Yet, perhaps such spaces could further nurture surrounding neighborhoods. The City of Tacoma and Metro Parks Tacoma have entered into an agreement to find out. We want to determine how the needs of the community can be served by these spaces through the fostering of volunteer stewardship, quality vegetation, and natural resource management plans. With your involvement, these spaces will become even greater Tacoma assets.

A draft of the plan for the slope were shared with the public in January. Now the City and Metro Parks are ready to share their completed plan. Below are some elements of the draft shared in January.

Slope Stability

For decades the slope has largely been left in its natural state, but that has led to some issues with stability and safety. In order to have loose soil stay put, a piece of land must not have a slope of more than 67%. (That's rise over run, times 100, for anyone else who's a little fuzzy on their middle school math). More than half of the Schuster Slope project area has slopes of more than 60%.

Geology says steep slopes like the ones along Schuster Parkway will continue to erode, seeking a comfortable equilibrium, meaning soil will continue to move downslope, causing erosion problems for anyone wanting the slope to stay put.

Processes like the growth and death of plants and their root structures, burrowing animals and insects, cycles of freezing and thawing, and weathering all contribute to the creation of a loose layer of soil on the surface of the slope. Those loose layers move downslope, exposing fresh soil beneath, which begins the process all over again, gradually but surely eroding the slope face.

Landscape Management

The City and Metro Parks propose a landscape management plan to improve conditions on the slope. Plants with soil-binding root systems can contribute to the stability of the slope by locking down that loose layer of dirt. The site currently faces challenges of invasive species, a lack of plant diversity and regeneration, and disease among the plants that are there.

To foster a healthy ecosystem on the slope, the City and Metro Parks will focus on restoring native vegetation. Invasive plants will be targeted for removal, with a goal of native plants making up more than 90% of the vegetation. Two out of every three trees will be evergreen, and a layered understory will be fostered, creating a dense root network to hold soil in place. This will have the added benefit of improving stormwater quality and impact, as water runs down the slope.

Public Safety

Stabilizing the slope reduces the threat of landslides, and trees will be assessed for safety. Another challenge for the area is its use for encampments of homeless people and drug users. Design elements will be introduced to reduce access for unauthorized uses, and to make the area more visible, and thus less attractive to those users.

Views

The Schuster Slope sits above the busy Schuster Parkway. Above the slope are a number of condos and apartments with residents and owners who value their views that include Commencement Bay and Mount Rainier. The growth of tall and/or dense vegetation threatens those views.

To address these concerns while still focusing on improving the slope stability through landscape management, the plan has a phased approach. A layered understory and canopy will be established, with regular pruning and maintenance, and targeted removal of some trees and plants.

What do you think? Is there anything you would like to see changed or added at this week's meeting?

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Comments

Stu

Some native plants and trees can help reduce erosion and slides, but they won’t prevent them. And procuring/planting/establishing such plants isn’t cheap.

If looking for a more permanent, attractive and protective solution, build terraced retaining walls. Then you’d gain some interesting real estate for parks, woodlands, views, etc.

Huge project? Sure. Time to get creative to make it more affordable. Maybe stack huge precast concrete bricks instead of using concrete pours. Devote an area where materials can be bought and dumped by the train carload and assemble at or near onsite. Use volunteers to oversee etching the name of every 2015 taxpayer in the wall a la (and no disrespect intended towards) Vietnam Vet memorial in DC as a unique way of satisfying arts requirement (is it still a requirement?) - encourage people to come and etch their own name.

Sorry, going off on tangents. Bottom line, I’d rather see public money invested in a more long-term, forward-thinking solution.

Engineer

Stu,
This strategy is likely a better long-term solution than cost-prohibitive retaining walls. The problem with retaining walls is that they are extremely expensive to do right, to the point that they can be cost-prohibitive, and when done cheaply tend to fail and require replacement. Vegetation and stormwater management can be better strategies, are much less expensive, and done right can be a good long-term solution in the right scenarios. I don’t know the specifics of this project, as I am not in City Hall reading the geotechnical reports with data about the soil types, but the City’s conclusion that vegetation management is the best long-term solution for this hillside is not a surprise to me. I suspect that the data that the engineers in City Hall are looking at tells them that there is not money to do a retaining wall, and that vegetation management will buy just as much time as a poorly-done (“cheap”) retaining wall, for much less money. That’s just my suspicion.
JD, Regarding the City’s failing infrastructure, that is a separate political problem that doesn’t just plague Tacoma. (Go drive around the older neighborhoods of Burien, Renton, or Auburn sometime. Your car’s struts will curse you for it!) I’ve been hearing from suburban cities for years that state and federal grant and funding programs provide all kinds of money for pet projects like new traffic signals, “safety” improvements, sculptures, and community centers, while providing zero dollars for things like water system upgrades and pavement preservation. Talk to your representatives in Olympia and the “other” Washington to get your state and federal dollars dedicated to the right programs.

JDHasty

I cannot speak for Burien or Auburn, but you cannot find a street in Renton that “your car’s struts will curse you for.”

“Talk to your representatives in Olympia and the “other” Washington to get your state and federal dollars dedicated to the right programs.”

FYI, Tacoma lead the lobbying effort to have the restrictions on what “transportation dollars” derived from State Motor Vehicle Fuel Taxes that were remitted to local jurisdictions relaxed. The City of Tacoma is actively fighting any efforts to dedicate a percentage of “State” grant dollars to preservation and maintenance.

JDHasty

FYI, Tacoma lead the lobbying effort to have the restrictions on what “transportation dollars” derived from State Motor Vehicle Fuel Taxes that were remitted to local jurisdictions could be spent on relaxed.

Terry

Hi Everybody. I say we build a mountain bike trail on Schuster Slope, and before we get any engineers involved, call in Evergreen MTB Alliance for help. This problem is nothing that a million bucks worth of gravel and concrete blocks plus the biggest volunteer project in City history can’t solve. And we drive out the homeless campers forever!